[Bug]: Terraform plan should give you the error if you are using HTTPS as the protocol while creating aws_lb_target_group and aws_lb_listener and do not provide certificate ARN

[DhruvinSoni30]

Terraform Core Version

1.4.6

AWS Provider Version

4.67.0

Affected Resource(s)

aws_lb_listener aws_lb_target_group

Expected Behavior

When using HTTPS as the protocol in the aws_lb_listener & aws_lb_target_group and if we don't specify the certificate_arn then terraform plan is not giving the error. When you run terraform apply then only it is giving the error.

Actual Behavior

When using HTTPS as the protocol in the aws_lb_listener & aws_lb_target_group and if we don't specify the certificate_arn then terraform plan should give the error that certificate_arn is not defined.

Relevant Error/Panic Output Snippet

Terraform plan is not giving error:

# module.alb.aws_lb_listener.application_load_balancer_listener will be created
  + resource "aws_lb_listener" "application_load_balancer_listener" {
      + arn               = (known after apply)
      + id                = (known after apply)
      + load_balancer_arn = (known after apply)
      + port              = 8000
      + protocol          = "HTTPS"
      + ssl_policy        = (known after apply)

Plan: 25 to add, 0 to change, 0 to destroy.

─────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────

Note: You didn't use the -out option to save this plan, so Terraform can't guarantee to take exactly these actions if you run "terraform apply" now.
C02CR96VMD6M:Splunk_Infrastructure dhruvins$ 

Terraform apply is giving the error

Error: creating ELBv2 Listener (arn:aws:elasticloadbalancing:us-east-2:765631733981:loadbalancer/app/buttercupgames-alb/12352cf60cf3918b): ValidationError: A certificate must be specified for HTTPS listeners
│   status code: 400, request id: f768511e-c630-47e0-88b1-cfce7b1d4965
│

Terraform Configuration Files

# Create listener
resource "aws_lb_listener" "application_load_balancer_listener" {
  load_balancer_arn = aws_lb.application_load_balancer.arn
  port              = 8000
  protocol          = "HTTPS"

  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.alb_target_group.arn
  }

  tags = {
    Name = "${var.project_name}-alb-listener"
    Env  = var.env
    Type = var.type
  }
}

# Create target group
resource "aws_lb_target_group" "alb_target_group" {
  name     = "${var.project_name}-tg-group"
  port     = 8000
  protocol = "HTTPS"
  vpc_id   = var.vpc_id

  lifecycle {
    create_before_destroy = true
  }

  health_check {
    healthy_threshold   = var.health_check["healthy_threshold"]
    interval            = var.health_check["interval"]
    unhealthy_threshold = var.health_check["unhealthy_threshold"]
    timeout             = var.health_check["timeout"]
    path                = var.health_check["path"]
    port                = var.health_check["port"]
  }

  tags = {
    Name = "${var.project_name}-alb-target-group"
    Env  = var.env
    Type = var.type
  }
}

Steps to Reproduce

Create application load balancer using terraform

Example snippet:

# Create listener
resource "aws_lb_listener" "application_load_balancer_listener" {
  load_balancer_arn = aws_lb.application_load_balancer.arn
  port              = 8000
  protocol          = "HTTPS"

  default_action {
    type             = "forward"
    target_group_arn = aws_lb_target_group.alb_target_group.arn
  }

  tags = {
    Name = "${var.project_name}-alb-listener"
    Env  = var.env
    Type = var.type
  }
}

# Create target group
resource "aws_lb_target_group" "alb_target_group" {
  name     = "${var.project_name}-tg-group"
  port     = 8000
  protocol = "HTTPS"
  vpc_id   = var.vpc_id

  lifecycle {
    create_before_destroy = true
  }

  health_check {
    healthy_threshold   = var.health_check["healthy_threshold"]
    interval            = var.health_check["interval"]
    unhealthy_threshold = var.health_check["unhealthy_threshold"]
    timeout             = var.health_check["timeout"]
    path                = var.health_check["path"]
    port                = var.health_check["port"]
  }

  tags = {
    Name = "${var.project_name}-alb-target-group"
    Env  = var.env
    Type = var.type
  }
}

Debug Output

No response

Panic Output

No response

Important Factoids

No response

References

No response

Would you like to implement a fix?

None

[github-actions[bot]]

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[DhruvinSoni30]

Hello Team,

Any update on this one?

CC: @justinretzolk